In the prior art, document FR-2 721 377 is already known that describes a connection device for assembling together two members. The device includes a movable hairpin-shape forming a pair of jaws. In order to space the jaws of the hairpin-shape apart, stationary spacer means are provided, and in order to move the hairpin-shape, cam means are provided including a pivotable lever that pivots about a pin and to which an eccentrically-mounted disk is associated. The device further includes a cage inside which the hairpin-shape, the spacer means, and the cam means are received. Thus, the hairpin-shape moves in the cage under the action of the eccentric disk that is actuated by the pivotable lever, and its jaws are spaced apart by the spacer means that are stationary in the cage. Consequently, the connection device requires the use of a stationary cage and of a movable hairpin-shape. In addition, other than the lever, the cam means include a movable pin that biases the hairpin-shape by means of a spring. As a result, actuation of the lever is difficult and requires significant force.